the cell of mr. nelson mandela. >> reporter: and into the tiny cells. this is where mandela spent almost two decades. a cold stone cubicle. no plumbing. a thin mat for sleeping. hard labor in the prison rock quarry. a hard life day in and day out. ahmed muhammed cusrata was a fellow political prisoner but now a retired member of parliament. one of mandela's closest friends. >> we were sentenced to life in imprisonment, and we knew that for political prisoners, life meant life. >> reporter: but he said mandela never asked for special treatment. in fact, he refused it. >> he could have been exempted from work at the quarry. he refused. 1977, 13 years after we were in prison, he was offered release. he refused. >> reporter: over the years in prison, mandela developed a unique friendship with this man. one of his guards, crito brand. >> i don't know at all who mandela was when i started at robben island. >> reporter: a warm friendship began to develop and one day brand broke all the rules for madiba as mandela was called by his friends. mandela's wife winni